Effects of restorative and adhesive curing methods on dentin bond strengths

Purpose: To evaluate the shear bond strengths of "one-bottle" adhesives to dentin when used with self-cured composite. Materials and Methods: 100 bovine teeth were ground to expose superficial dentin, which was polished to 600-grit. The dentin was etched for 15 s with 35% phosphoric acid, rinsed, and blotted with tissue paper. The surface remained visibly moist for all specimens. The following adhesives were applied to the etched dentin according to manufacturers' directions: Scotchbond Multi-Purpose (in its visible light-cured [VLC] and self-cure modes) as a control, One-Step (VLC only), OptiBond Solo Plus (VLC only), Prime & Bond NT (VLC) and Prime & Bond NT Dual-Cure. For each adhesive, specimens were bonded with a self-cure composite, while 10 were bonded with a VLC composite as a control. After 24 hrs water storage, shear bond strengths were determined using an Instron universal testing machine. Data were analyzed using two-way ANOVA, Tukey's test, and Student's t-tests. Results: Using the light-cured composite, mean bond strengths ranged from 11.0 MPa for light-cured Prime & Bond NT to 26.3 MPa for OptiBond Solo Plus. Using the self-cure composite, mean bond strengths ranged from 0.0 for light-cured Prime & Bond NT to 21.4 MPa for One-Step. Two adhesives, light-cured Prime & Bond NT and OptiBond Solo Plus, had significantly lower bond strengths when used with the self-cure composite.